1. Field
The present invention relates to systems, apparatus and methods for characterizing one or more analytes in human breath. Such systems, apparatus and methods may be useful in a variety of applications, for example, such as in personal health monitoring, clinical diagnostics, safety and law enforcement monitoring, and others.
2. Background
A problem facing the medical community is noninvasive disease monitoring and management. Blood analysis is accurate and quantitative, but is invasive, and the pain associated with routine blood sampling leads to low compliance, particularly amongst children and the elderly. Urine analysis, while noninvasive, has been criticized as being inaccurate. Urine analysis is also typically performed using a colorimetric assay, which involves interpretation, and thus poses the problem of being non-quantitative. Thus, these techniques are far from ideal and leave much to be desired.
Low cost, miniature, non-invasive biosensors capable of analyzing small quantities of samples clearly are needed. The need is particularly pronounced for biosensors that are easy to use, have fast response times, and good operational stability, which features are needed in many biochemical and clinical diagnostic applications, such as breath analysis.
Calorimetry is a very powerful and effective investigative tool for analyzing biochemical reactions. Unlike most other biochemical sensors, those based on thermal transducers can be mounted in a protected way that prevents fouling of the base transducer and thereby minimizes the consequential drift in the sensor's response. This provides a significant advantage of operational stability. Also, thermal transducers are not fundamentally limited by the type of interactant (e.g., enzymes, binding agents, etc.) that is used to interact with the analyte of interest to generate a measurement signal. This provides versatility in the interactant used in conjunction with the thermal sensor. Also, the ability to follow the progress of a reaction continuously as a function of time or reactant concentration has many research and clinical applications with far reaching consequences, such as in breath analysis.
Here, we describe a novel form of thermal sensing for breath or related gas analysis.